TABLE 4.
Multinomial regression analysis for patients who live closer to highways than major roads, with outcomes of three classes of airway hyper-responsiveness with reference to the normal group (PC20 >16 mg/mL [n=160])
|
PC20 class Independent variables |
B | P | OR (95% CI) |
|---|---|---|---|
| Severe (n=9) | |||
| Age, years | 0.02 | 0.396 | 1.02 (0.97–1.08) |
| Ambient temperature, °C | 0.01 | 0.784 | 1.01 (0.94–1.09) |
| Relative humidity, % | 0.04 | 0.356 | 1.04 (0.96–1.13) |
| FEV1, % predicted | −0.08 | 0.010 | 0.92 (0.87–0.98) |
| Taking ICS* | 1.19 | 0.300 | 3.27 (0.35–30.86) |
| Taking LABA | 1.13 | 0.323 | 3.10 (0.33–29.24) |
| Female | 2.33 | 0.045 | 10.32 (1.05–101.17) |
| Within 300 m of highway | 1.78 | 0.125 | 5.92 (0.61–57.35) |
| Moderate (n=17) | |||
| Age, years | −0.01 | 0.637 | 0.99 (0.95–1.03) |
| Ambient temperature, °C | 0.01 | 0.739 | 1.01 (0.96–1.07) |
| Relative humidity, % | −0.02 | 0.487 | 0.98 (0.94–1.03) |
| FEV1, % predicted | −0.10 | <0.010 | 0.90 (0.86–0.95) |
| Taking ICS* | 0.06 | 0.939 | 1.06 (0.21–5.30) |
| Taking LABA | 1.16 | 0.186 | 3.19 (0.57–17.82) |
| Female | 1.21 | 0.057 | 3.36 (0.97–11.72) |
| Within 300 m of highway | −0.22 | 0.701 | 0.80 (0.26–2.49) |
| Mild (n=44) | |||
| Age, years | −0.01 | 0.257 | 0.99 (0.96–1.01) |
| Ambient temperature, °C | 0.03 | 0.100 | 1.03 (0.99–1.08) |
| Relative humidity, % | 0.06 | 0.002 | 1.07 (1.02–1.11) |
| FEV1, % predicted | −0.03 | 0.041 | 0.97 (0.94–1.00) |
| Taking ICS* | 1.36 | 0.010 | 3.88 (1.39–10.87) |
| Taking LABA | −0.28 | 0.658 | 0.76 (0.22–2.62) |
| Female | 0.12 | 0.775 | 1.12 (0.51–2.49) |
| Within 300 m of highway | −0.21 | 0.591 | 0.81 (0.38–1.74) |
*
Fluticasone equivalent. FEV1 Forced expiratory volume in 1 s; ICS Inhaled corticosteroid; LABA Long-acting beta2-agonist; PC20 Provocative concentration of methacholine causing a 20% decline in FEV1